Fluid quick disconnect couplings are well known in many industries, including industrial, aerospace, automotive, agricultural, etc. The need to quickly and reliably attach a fluid source to a hose or fluid client has made the quick disconnect coupling a standard component of most fluid systems. Quick disconnects improve performance by simplifying connections/disconnections and preventing fluid leakage, and typically eliminate the need for special tools to engage and disengage the coupling since most disconnects are actuated by hand.
There are a wide variety of fluid quick disconnect couplings in the art. Snap type (ball latching) quick disconnects are designed with a spring loaded ball latching mechanism that automatically locks the two halves of the fitting together when they are pushed together. When the releasing sleeve is pulled back, the internal end and external ends quickly disengage from each other. This quick release feature is advantageous in designs that require numerous connections throughout the life cycle of the product because they are so simple to operate. Alternatively, non-latching quick disconnects are used in applications where quick serviceability in a compact envelope is required. Typically, a non-latching quick disconnect is selected when a portion of the device requires frequent change out or when the releasing sleeve may be inaccessible. No shut-off quick disconnects are used when high flow rates are required. They are generally limited to applications involving low pressure air or other non-hazardous gases because the fluid is not contained in either half of the assembly upon disconnection. In single shut-off quick disconnects, the internal half of the assembly contains a valve preventing flow from escaping. This design is advantageous when one wishes to fill or evacuate pressure from a chamber or portable device and then disconnect the fill line. Double shut-off quick disconnects have shut-off valves within both the internal and external ends. These shut-off valves retain pressure in both fluid lines when the assembly is disconnected. This is ideal when the fluid is a liquid, an expensive gas, or flammable gas (also consider a “dry break” quick disconnect).
In many industries, such as in the mining industry, a haul truck or excavator may have the need to supply multiple fluids on site to machinery or other vehicles. Fluids such hydraulic oil, transmission oil, coolant, and the like are supplied by the haul truck to the machinery through hoses with quick disconnect connectors. One issue that arises in this environment and similar situations is that simply color coding the hoses and disconnects for the specific fluids does not ensure that the user will apply the proper connections. Dirt, grease, and spillage can obscure color codings and markings, and lead to incorrect connections. For this reason, each fluid must have a different mechanical connection to prevent the wrong fluid from being delivered to the machinery.
Non-interchangeability is most simply achieved by progressively increasing the sizes of the couplings, including valves, seals, springs, etc. However, this approach has several shortcomings. First, different sized couplings will have different flow rate performances (the smallest inner diameter will have the highest pressure drop and vice versa), which requires that the user must assess which fluids will work best with each sized coupling based on viscosity and other fluid properties in order to maximize the performance of the fluid transfers. Second, by requiring each coupling to have different sizes and different components (springs, seals, etc.), manufacturing costs are increased for each variation of the coupling.
The industry is in need of a quick disconnect coupling that can assume multiple configurations made substantially of common components and achieving an identical flow path, eliminating the need to analyze which quick disconnect would be best served for a particular fluid.